L-精氨酸对脂多糖诱导大鼠肺损伤的保护作用及其机制的研究

目的：观察一氧化氮供体L-精氨酸（L-Arg）对脂多糖诱导大鼠肺损伤炎症反应和核因子-κB（NF-κB）信号通路的影响,探讨L-Arg对肺损伤的保护作用及其机制。方法：健康雄性SD大鼠采用舌下静脉注射脂多糖（LPS）复制肺损伤模型,分别于给予LPS3h和6h后给予生理盐水（对照组及LPS组,ip）和L-Arg（500mg/kgip）（L-Arg治疗组）,治疗3h。每组8只动物。免疫组化染色分析肺组织中NF-κB的核移位;逆转录多聚酶链反应（RT-PCR）检测肺组织细胞间粘附分子-1（ICAM-1）基因表达;放射免疫法分别测定肺组织中肿瘤坏死因子α（TNF-α）和白介素6（IL-6）的含量;光镜观察肺组织病理变化。结果：与对照组比较,大鼠肺损伤后NF-κB活化,明显从细胞浆移位于细胞核,表达量也显著增加;ICAM-1基因表达上调;肺组织中TNF-α、IL-6含量明显升高。肺损伤3h用L-Arg治疗3h后,NF-κB从细胞浆向细胞核的移位被明显限制,NF-κB的表达量、肺组织中TNF-α、IL-6含量明显低于相应的LPS组,肺组织病理改变减轻;肺损伤6h用L-Arg治疗3h对LPS引起的以上变化没有明显影响。结论：LPS3h后给予L-Arg可减轻内毒素性肺损伤,抑制核因子的活化,在一定程度上阻断NF-κB相关信号通路的传导,减轻炎症反应是其机制之一。     

硫化氢对大鼠内毒素性急性肺损伤肺泡表面活性物质的影响

目的：观察脂多糖（LPS）所致内毒素性急性肺损伤（ALI）大鼠肺泡表面活性物质（PS）的变化及硫化氢（H2S）对PS的影响,探讨H2S对肺脏的作用机制。方法：雄性SD大鼠共48只,随机分为6组（n=8）：空白对照组、LPS组、LPS＋NaHS低、中、高剂量组、LPS＋PPG组。空白对照组给予生理盐水,LPS组给予LPS,LPS＋NaHS低、中、高剂量组和LPS＋PPG组分别在给予LPS3h时腹腔注射低、中、高剂量氢硫化钠（NariS）或炔丙基甘氨酸（PPG）。各组均于给予生理盐水或LPS6h时电镜下观察肺泡Ⅱ型上皮细胞（AEC-Ⅱ）的形态改变,检测血浆中H2S含量、肺组织中胱硫醚-γ-裂解酶（CSE）活性、肺泡灌洗液（BALF）中总蛋白（1P）和总磷脂（TPL）含量、及肺组织中肺泡表面活性蛋白A、B、C（SP-A、B、C）mRNA表达的变化。结果：①与空白对照组比较,LPS组AEC-Ⅱ超微结构明显受损,血浆中H2S含量、肺组织中CSE活性、BALF中TPL的含量、及肺组织中SP-A、B、CmRNA表达均明显降低（P〈0．05,P〈0．01）,BALF中TP的含量明显增加（P〈0．01）;②与LPS组比较,LPS＋NaHS低、中、高剂量组,AEC-Ⅱ超微结构均有所恢复,血浆中H2S含量、肺组织中CSE海性、SP-AmRNA表达均明显升高（P〈0．05,P〈0．01）;LPS＋NaHS中、高剂量组BALF中吼含量明显增高,SP-BmRNA表达升高（P〈0．05）;LPS＋NaHS高剂量组BALF中,IP含量明显降低（P〈0．05）;LPS＋NaHS各剂量组SP-CznRNA表达无明显变化;③与LPS组比较,LPS＋PPG组AEC-Ⅱ超微结构仍损伤严重,血浆中H2S含量、肺组织中CSE活性、BALF中TPL的含量、及肺组织中SP-A、B、CmRNA表达均明显降低（P〈0．05）,BALF中TP的含量明显升高（P〈0．05）。结论：PS降低是内毒素性ALI的重要病理生理过程,H2S对LPS诱导的ALI有保护性作用,其机制可能与H2S对PS的调节有关。     

葛根素对脂多糖导致的大鼠急性肺损伤组织中水通道蛋白-1的影响

目的:观察葛根素对脂多糖诱导的急性肺损伤大鼠肺组织水通道蛋白-1(AQP1)表达、病理形态学、湿干比等的影响,探讨其对急性肺损伤的保护作用.方法:健康Wistar大鼠36只,采用腹腔内注射脂多糖(lipopolysaccharide,LPS)法复制急性肺损伤动物模型.将大鼠随机分为盐酸对照组(对照组)、LPS损伤组(损伤组)和葛根素+LPS组(葛根素组).结果:光镜下见对照组肺泡结构清晰,肺泡腔及支气管腔未见明显炎细胞及渗出物.LPS组镜下可见肺组织水肿,表面可见暗红色点、片状出血,大量炎性细胞浸润,肺泡间隔明显增厚,葛根素+LPS组损伤较LPS组明显减轻.LPS组湿干比较对照组增高,葛根素组湿干比较LPS组降低.LPS组AQP1蛋白表达较对照组减少,葛根素组肺组织AQP1蛋白表达较LPS组明显增加.结论:葛根素对脂多糖所致的大鼠急性肺损伤具有保护作用.     

急性肺损伤大鼠肺组织TOLL样受体4及CD14mRNA的表达

目的 探讨内毒素致急性肺损伤大鼠肺组织TOLL样受体4及CD14 mRNA表达的变化.方法 24只雄性Wistar大鼠随机分为2组:对照组、LPS模型组,每组再分为4 h和8 h两个亚组.尾静脉注射脂多糖(LPS)(10 mg/kg)建立大鼠急性肺损伤模型.检测大鼠动脉血气、肺体指数,实时荧光定量PCR测定肺组织TOLL样受体4及CD14 mRNA的表达,并观察肺组织病理变化.结果 与对照组相比,模型组4 h和8 h时大鼠肺组织中的TLR4及CD14 mRNA表达均显著增高(P＜0.05或P＜0.01).病理学观察显示,模型组大鼠肺组织出现出血及坏死.结论 内毒素致急性肺损伤的发病机制可能与TLR4及CD14 mRNA的表达升高有关.     

急性肺损伤大鼠肺组织基质金属蛋白酶2及其抑制因子蛋白和mRNA的表达

目的探讨内毒素致急性肺损伤（ALI）大鼠肺组织核转录因子-κB（NF-κB）、基质金属蛋白酶2（MMP-2）及其抑制因子（TIMP-2）蛋白和mRNA表达的变化。方法 20只雄性Wistar大鼠随机分为2组：对照组、LPS模型组,每组再分为4 h和8 h两个亚组。尾静脉注射脂多糖（LPS）（10 mg/kg）建立大鼠急性肺损伤模型。检测血白细胞计数、支气管肺泡灌洗液（BALF）蛋白含量,采用免疫组化ABC法和实时荧光定量PCR分别测定肺组织NF-κB、MMP-2、TIMP-2蛋白及其mRNA的表达,并观察肺组织病理变化。结果与对照组相比,模型组4 h和8 h时大鼠肺组织中的NF-κB、MMP-2蛋白染色阳性面积率及其mRNA表达均显著增高（P〈0.01）、TIMP-2蛋白染色阳性面积率及其mRNA表达均明显降低（P〈0.05或P〈0.01）。病理学观察显示,模型组大鼠肺组织出现出血及坏死。结论内毒素致急性肺损伤的发病机制可能与NF-κB、MMP-2蛋白及其mRNA表达升高、TIMP-2蛋白及其mRNA表达降低有关。     

慢性阻塞性肺疾病大鼠模型病变特点的研究

目的 研究慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)大鼠模型肺表面活性物质相关蛋白A(Surfactant protein A, SP-A)表达及肺组织超微结构变化特点.方法 运用气管内滴注脂多糖加烟熏28天法建立COPD大鼠模型.观察大鼠一般状态、用免疫组化法检测SP-A表达及透射电镜观察肺泡Ⅱ型上皮细胞超微结构变化.结果 各组SP-A平均肺泡阳性细胞数与空白组比较有显著差异(P＜0.01).结论 用气管内滴注脂多糖加烟熏28天法建立的COPD大鼠模型可靠,造模停止两周后模型稳定.     

环孢菌素A对脂多糖诱导的小鼠急性肺损伤的保护作用

目的：探讨线粒体渗透性转换孔道抑制剂环孢菌素A（CsA）对脂多糖（LPS）诱导的小鼠急性肺损伤可能的保护作用。方法：LPS 4 mg/kg气管内滴入复制小鼠急性肺损伤模型,实验随机分为5组（n=24）：分别为正常对照组、LPS组、地塞米松组、CsA组和CsA＋苍术苷组。6 h后小鼠处死,测定各组支气管肺泡灌洗液乳酸脱氢酶（LDH）的含量,酶联免疫吸附法测定肺组织匀浆液TNF-α浓度,测定肺组织湿/干重比和肺毛细血管通透性指数。结果：气管内滴入LPS 6 h后,CsA组与LPS组相比,肺泡灌洗液中LDH活性降低,肺组织匀浆液TNF-α浓度下降,肺组织湿/干重比、肺毛细血管通透性指数均明显下降,但CsA＋Atr组与LPS组相比无明显区别。结论：环孢菌素A对脂多糖诱导的小鼠急性肺损伤有保护作用,其机制可能与其抑制线粒体渗透性转换孔道的开放有关。     

莲心碱对LPS诱导小鼠急性肺损伤的保护作用

目的探讨莲心碱对脂多糖(lipopolysaccharide,LPS)诱导的小鼠急性肺损伤(ALI)的作用。方法BALB/c小鼠随机分为对照组、LPS组、LPS+莲心碱(2、4、8 mg/kg)组、地塞米松(5 mg/kg)组,鼻腔滴入法建立LPS诱导的急性肺损伤模型。12 h后,组织学观察肺组织的病理学变化;ELISA检测肺泡灌洗液(BALF)中TNF-α、IL-6和IL-1β的含量;Wright-Giemsa染色检测BALF中中性粒细胞数;BCA法检测总蛋白含量;Evans blue检测肺毛细血管通透性;分光光度法检测肺匀浆上清中MPO的活性、MDA的含量、SOD的活性、GSH的含量;流式细胞术检测肺组织中ROS的含量。结果 LPS组可见肺组织具有炎性细胞浸润、支气管肺泡壁增厚和肺充血现象,而莲心碱组可以改善肺损伤情况;LPS组BALF中TNF-α、IL-6、IL-1β的含量明显增加、中性粒细胞数和总蛋白量显著增多,肺毛细血管通透性、MPO活性和MDA含量增加,SOD活性和GSH含量降低,ROS含量增加,而莲心碱组能够降低BALF中TNF-α、IL-6、IL-1β的含量,减少中性粒细胞数和总蛋白量,降低肺毛细血管通透性,降低MPO活性和MDA含量,增加SOD活性和GSH含量,降低ROS的含量。结论莲心碱可通过抗炎抗氧化作用保护LPS诱导的小鼠急性肺损伤。     

L-精氨酸对实验性大鼠急性肺损伤的保护作用

目的 探讨一氧化氮(NO)前体物质L-精氨酸(L-Arg)在内毒素(LPS)致大鼠急性肺损伤中的作用.方法 SD大鼠24只随机分为空白对照组、LPS组和L-Arg(500 mg/kg)组.腹腔注射LPS(100 μg/kg)复制急性肺损伤动物模型.在LPS注射2 h后,取大鼠肺称其湿重与干重,计算肺湿干比,测定肺灌洗液蛋白含量和白细胞数量,并进行肺组织病理学检查.结果 与对照组相比,LPS组肺湿干比、肺灌洗液蛋白含量和白细胞计数显著增高(P<0.01,n=8),病理学切片见急性肺损伤性变化;与LPS组相比,L-Arg组肺湿干比、肺灌洗液蛋白含量和白细胞计数显著降低(P<0.01,n=8),肺组织急性损伤显著减轻.结论 L-Arg具有抗LPS致急性肺损伤的作用.     

人工合成红景天苷对大鼠急性肺损伤的保护作用

为了研究人工合成红景天苷(salidroside,Sal)对脂多糖(lipopolysaccharide,LPS)诱导大鼠急性肺损伤(acute lung injury,ALI)的保护作用及其机制,将雄性Sprague-Dawley大鼠随机分为生理盐水对照组、3 mg/kg LPS损伤组、不同剂量Sal干预组(5、20和80 mg/kg)以及5 mg/kg地塞米松(dexamethasone,Dex)干预组,气管内滴注LPS建立ALI模型,在LPS造模前0.5 h腹腔给予人工合成Sal或Dex,造模6 h后处死动物。计量肺湿/干重比值(wet/dry weight ratio,W/D),苏木素-伊红染色观测肺组织病理形态学变化和肺损伤评分。用瑞氏染色计数肺泡灌洗液(bronchoalveolar lavage fluid,BALF)离心沉淀的中性粒细胞(polymorphonuclear leukocyte,PMN),用BCA法测定BALF离心上清蛋白含量,并用酶联免疫吸附法测定TNF-α、IL-1β和IL-6的含量。测定肺组织中髓过氧化物酶(myeloperoxidase,MPO)和丙二醛(malondialdehyde,MDA)含量,Western blot检测肺组织中磷酸化NF-κB和总NF-κB蛋白表达水平。结果显示,与LPS组比较,人工合成Sal能减轻肺组织损伤程度,降低肺损伤评分和W/D比值(P0.05),减少BALF中PMN计数、蛋白含量以及炎症因子水平(P0.05),降低肺组织中MPO和MDA含量(P0.05),抑制肺组织中磷酸化NF-κB蛋白的表达(P0.05)。以上结果提示,人工合成Sal对LPS诱导的ALI具有保护作用,其机制与抑制肺组织NF-κB蛋白磷酸化以及减少PMN在肺内聚集有关。     

模拟高原环境下高原肺水肿大鼠模型的建立

目的在人工实验舱模拟高原环境下,探讨建立高原肺水肿大鼠模型的条件。方法 Wistar大鼠,雌雄各半,随机分为5组:空白对照组、低氧24 h组、低氧48 h组、低氧72 h组、低氧7 d组,测定大鼠肺组织含水量,肺组织中TNF-α、IL-6含量及病理改变。结果与正常对照组相比,低氧24、48、72 h组大鼠肺组织含水量依次为(81.58±0.86)%、(82.13±0.57)%、(82.21±0.88)%,高于正常对照组(78.72±0.52)%,肺组织中IL-6依次为(329.30±133.58)、(323.92±127.42)、(506.29±197.19)pg/mL,TNF-α依次(221.08±20.26)、(208.05±20.33)、(244.63±51.53)pg/mL,高于正常对照组IL-6(187.26±69.49)pg/mL,TNF-α为(91.81±22.24)pg/mL。低氧7d组肺组织含水量(81.47±0.65)%、肺组织中IL-6(241.33±83.60)pg/mL、TNF-α(109.99±31.98)pg/mL,均显著低于低氧72h组,病理学结果显示72h组肺组织有炎性细胞浸润,肺泡壁有明显的充血和水肿。结论模拟海拔5000 m环境,建立大鼠肺水肿模型的较好的时间为72 h。     

钙敏感受体通过JNK途径参与内毒素心肌损伤*

目的: 观察内毒素所致的心肌损伤中,钙敏感受体(CaSR)对c-Jun氨基末端激酶 (JNK)途径的影响。方法: 腹腔注射内毒素(5 mg/kg)制作新生大鼠内毒素心肌损伤模型,Wistar新生大鼠随机分为6组:对照组、内毒素组、CaSR激动剂组、CaSR抑制剂组、JNK抑制剂组、CaSR抑制剂+JNK抑制剂组。HE染色观察心肌形态, 测定血清乳酸脱氢酶(LDH)含量,PCR检测IL-6的mRNA表达,Western blot检测CaSR及JNK的蛋白表达。结果: 与对照组相比,内毒素组心肌损伤加重,LDH含量、IL-6的mRNA表达、CaSR和JNK的蛋白表达均明显增加(P＜0.05)。与内毒素组比较,CaSR激动剂组心肌损伤加重,LDH含量、IL-6的mRNA表达、CaSR和JNK的蛋白表达增加(P＜0.05); CaSR抑制剂组心肌损伤减轻,LDH含量、CaSR和JNK的蛋白表达减少(P＜0.05);JNK抑制剂组心肌损伤进一步减轻,LDH含量、IL-6的mRNA表达、CaSR和JNK的蛋白表达均减少(P＜0.05);CaSR抑制剂+JNK抑制剂组心肌损伤明显减轻,LDH含量、IL-6的mRNA表达、CaSR和JNK的蛋白表达进一步减少(P＜0.05)。结论: CaSR可能通过JNK途径参与内毒素所致的心肌损伤。     

Effects of pulmonary surfactant and surfactant protein A on phagocytosis of fractionated alveolar macrophages: relationship to starvation.

Pulmonary surfactant isolated from bronchoalveolar lavage fluid of rat lung contained a high content of surfactant protein A (SP-A) in starved for 2 days compared to fed controls, but this phenomena returned to baseline following more than 4 days starvation. As determined by immunoperoxidase staining of lung sections using SP-A antibody, SP-A could be consistently observed in nonciliated bronchiolar (Clara) cells, alveolar type II cells and some alveolar macrophages (AM). Fc receptor-mediated phagocytosis of AM was enhanced by SP-A, which was dependent on the dosis and reached a maximum at 10 micrograms of SP-A/ml. Antibody to SP-A completely inhibited the enhanced response of phagocytosis. When exposed AM subpopulations, separated into four fractions (I, II, III and IV) by discontinuous Percoll gradient, to SP-A or pulmonary surfactant prepared from rats fed and starved for 2 days enhanced their phagocytic activity in high dense cells (III and IV), particularly to SP-A and pulmonary surfactant from rats starved for 2 days. Whereas little change in lower dense fractions (I and II) were seen in all exposures except for SP-A that enhanced the cells of fraction II. These results supported the concept that pulmonary surfactant and its apoprotein, SP-A, are a factor to regulate lung defense system including activation of AM that undergo different processes following starvation.     

KLF2 attenuates bleomycin-induced pulmonary fibrosis and inflammation with regulation of AP-1

Pulmonary fibrosis (PF) is a chronic, fibrosing interstitial pneumonia and devastating disease. Here we investigated the potential roles of Kruppel-like factor 2 (KLF2) on pulmonary fibrosis and inflammation response. A mouse model of pulmonary fibrosis was established by intratracheal injection of bleomycin (BLM). The mRNA and protein levels of KLF2 were assayed by RT-PCR and Western blotting respectively. The extent of lung fibrosis was determined using hematoxylin and eosin (HE) staining and Masson's trichrome staining, and the hydroxyproline content was quantified. RT-PCR was used to evaluate the mRNA expression of collagen type 1a1 (col1a1), col3a1, α-SMA, TNF-α, IL-1β and IL-6. The concentrations of TNF-α, IL-1β, and IL-6 in bronchoalveolar lavage fluid (BALF) and lung tissue were examined by ELISA. Also, the effects of KLF2 on activator protein-1 (AP-1) were evaluated by measuring the c-Jun and c-Fos protein levels. We found that KLF2 was remarkably downregulated in BLM-treated rats, both in mRNA and protein levels. Additionally, overexpression of KLF2 attenuated the destruction of the alveolar space and pulmonary interstitial collagen hyperplasia, and deposition reduced the expression of col1a1, col3a1, and α-SMA, and blocked the production of TNF-α, IL-1β, and IL-6 in BALF and lung tissue in vivo. Moreover, adenoviral transduction of KLF2 inhibited TGF-β1-induced expression of col1a1, col3a1, and α-SMA in vitro. Mechanically, BLM up-regulated c-Jun and c-Fos expression, which was impeded by KLF2 overexpression. Taken together, our data indicate that KLF2 attenuates pulmonary fibrosis and inflammation, possibly through the regulation of AP-1.     

低氧联合LPS刺激对星形胶质细胞中炎性因子和BNIP3表达的影响*

目的:探讨在低氧联合脂多糖(LPS)作用下,星形胶质细胞中B淋巴细胞瘤-2/腺病毒E1B 19-kD相互作用蛋白3(BNIP3)的表达和炎症反应变化。方法:将体外培养的原代星形胶质细胞和神经元进行下列分组:常氧组、LPS组、低氧组和LPS+低氧组(每组设置3个复孔)。LPS处理后,低氧组和LPS+低氧组放入低氧细胞孵箱,LPS组和常氧组放入正常的细胞孵箱。LPS浓度:100 ng/ml,氧气浓度为0.3%。处理时间为24 h。原代的星形胶质细胞进行上述的分组,时间点设为6 h、12 h和24 h。Western blot检测BNIP3的表达变化,RT-PCR和ELISA分别检测星形胶质细胞的肿瘤坏死因子-ɑ(TNF-ɑ)、白细胞介素-1β(IL-1β)和白细胞介素6(IL-6)mRNA水平变化和分泌情况。结果:与常氧组比较,低氧组炎症因子的表达没有变化,LPS组和LPS＋低氧组的炎症因子TNF-ɑ、IL-1β和IL-6 mRNA水平升高(P＜0.01);与LPS组比较,LPS＋低氧组炎症因子IL-1β和IL-6 mRNA水平进一步升高(P＜0.05,P＜0.01)。与常氧组比较,低氧组炎症因子的分泌水平没有变化,LPS组和LPS＋低氧组的炎症因子TNF-ɑ和IL-6 分泌水平升高(P＜0.01),IL-1β的水平没有变化;与LPS组比较,LPS＋低氧组炎症因子TNF-ɑ和IL-6分泌水平没有进一步升高。BNIP3在体外培养的神经元和星型胶质细胞中都有表达;在星形胶质细胞中,与常氧组比较,LPS组BNIP3的表达没有变化,低氧组和LPS+低氧组BNIP3的表达明显增加(P＜0.01);在神经元中,与常氧组比较,LPS组BNIP3的表达没有变化,低氧组和LPS+低氧组BNIP3的表达增加(P＜0.05,P＜0.01);与神经元的低氧组比较,星形胶质细胞的低氧组BNIP3的表达增加更明显(P＜0.01)。在星形胶质细胞中LPS联合低氧刺激6、12、24 h后BNIP3蛋白的表达,与常氧组相同时间点比较,LPS组BNIP3的表达没有变化,低氧组和LPS+低氧组BNIP3的表达增加(P＜0.05,P＜0.01);与低氧组相同时间点比较,6 h和12 h的LPS＋低氧组BNIP3的表达增加的更高(P＜0.01)。结论:低氧联合LPS刺激可以增强星形胶质细胞的炎症反应,LPS能增加低氧下星形胶质细胞中BNIP3的表达,提示BNIP3在星形胶质细胞的炎性反应中可能具有一定的调节作用。     

Prostaglandins mediate the fetal pulmonary response to intrauterine inflammation

Intra-amniotic (IA) lipopolysaccharide (LPS) induces intrauterine and fetal lung inflammation and increases lung surfactant and compliance in preterm sheep; however, the mechanisms are unknown. Prostaglandins (PGs) are inflammatory mediators, and PGE(2) has established roles in fetal lung surfactant production. The aim of our first study was to determine PGE(2) concentrations in response to IA LPS and pulmonary gene expression for PG synthetic [prostaglandin H synthase-2 (PGHS-2) and PGE synthase (PGES)] and PG-metabolizing [prostaglandin dehydrogenase (PGDH)] enzymes and PGE(2) receptors. Our second study aimed to block LPS-induced increases in PGE(2) with a PGHS-2 inhibitor (nimesulide) and determine lung inflammation and surfactant protein mRNA expression. Pregnant ewes received an IA saline or LPS injection at 118 days of gestation. In study 1, fetal plasma and amniotic fluid were sampled before and at 2, 4, 6, 12, and 24 h after injection and then daily, and fetuses were delivered 2 or 7 days later. Amniotic fluid PGE(2) concentrations increased (P < 0.05) 12 h and 3-6 days after LPS. Fetal lung PGHS-2 mRNA and PGES mRNA increased 2 (P = 0.0084) and 7 (P = 0.014) days after LPS, respectively. In study 2, maternal intravenous nimesulide or vehicle infusion began immediately before LPS or saline injection and continued until delivery 2 days later. Nimesulide inhibited LPS-induced increases in PGE(2) and decreased fetal lung IL-1β and IL-8 mRNA (P ≤ 0.002) without altering lung inflammatory cell infiltration. Nimesulide decreased surfactant protein (SP)-A (P = 0.05), -B (P = 0.05), and -D (P = 0.0015) but increased SP-C mRNA (P = 0.023). Thus PGHS-2 mediates, at least in part, fetal pulmonary responses to inflammation.     

Low-dose erythropoietin aggravates endotoxin-induced organ damage in conscious rats

Endotoxin shock can induce the production of several inflammatory mediators such as TNF-α, IL-6, and IL-1β, leading to multiple organ dysfunction and death. Erythropoietin (EPO) has been found to interact with its receptor (EPO-R), expressed in a wide variety of non-hematopoietic tissues, to induce a range of pleiotropic cytoprotective actions. We investigated the effects of low doses of EPO (300 U/kg, intravenous administration) on the physiopathology and cytokine levels in endotoxin shock in conscious rats. Endotoxin shock was induced by intravenous injection of Escherichia coli lipopolysaccharide (20 mg/kg) in conscious rats. Mean arterial pressure (MAP) and heart rate (HR) were continuously monitored for 48 h after LPS administration. Levels of biochemical and cytokine parameters, including glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), blood urea nitrogen (BUN), creatinine (Cre), lactic dehydrogenase (LDH), and creatine phosphokinase (CPK) were measured at 0, 1, 3, 6, 9, 12, 18, 24, and 48 h after sepsis. Serum TNF-α, IL-6, and IL-1β level was measured at 1 h after sepsis. Endotoxin shock significantly increased blood GOT, GPT, BUN, Cre, LDH, CPK, TNF-α, IL-6, IL-1β levels, and HR, while it decreased MAP. EPO further increased the markers of organ injury (GOT, GPT, BUN, Cre, LDH, and CPK), inflammatory biomarkers (TNF-α, IL-6, and IL-1β) and did not affect MAP and HR after LPS. EPO disserved endotoxin shock-induced liver, kidney, lung, and small intestine damage in conscious rats. In conclusion, pre-treatment with low doses of EPO increased the release of TNF-α, IL-6, and IL-1β, along with aggravating endotoxin shock-induced markers of organ injury in conscious rats.